title: Bleeders, bleeding rates, and bleeding score.
abstract: Bleeding symptoms are frequently reported even in otherwise healthy subjects, and differentiating a normal subject from a patient with a mild bleeding disorder (MBD) can be extremely challenging. The concept of bleeding rate, that is, the number of bleeding episodes occurring within a definite time, could be used as the unifying framework reconciling the bleeding risk observed in congenital and acquired coagulopathies into a single picture. For instance, primary prevention trials have shown that the incidence of non-major bleeding symptoms in normal subjects is around five per 100 person-years, and this figure is in accordance with the number of hemorrhagic symptoms reported by normal controls in observational studies on hemorrhagic disorders. The incidence of non-major bleeding in patients with MBDs (e.g. in patients with type 1 VWD carrying the C1130F mutation) is also strikingly similar with that of patients taking antiplatelet drugs, and the incidence in moderately severe bleeding disorders (e.g. type 2 VWD) parallels that of patients taking vitamin K antagonists. The severity of a bleeding disorder may therefore be explained by a bleeding rate model, which also explains several common clinical observations. Appreciation of the bleeding rate of congenital and acquired conditions and of its environmental/genetic modifiers into a single framework will possibly allow the development of better prediction tools in the coming years and represents a major scientific effort to be pursued.
authors.affiliation: Department of Cell Therapy and Hematology, Hemophilia and Thrombosis Center, San Bortolo Hospital, Vicenza, Italy. tosetto@hemato.ven.it
authors.forename: A
authors.initials: A
authors.lastname: Tosetto
authors.forename: G
authors.initials: G
authors.lastname: Castaman
authors.forename: F
authors.initials: F
authors.lastname: Rodeghiero
mesh_terms: D001778:Blood Coagulation Disorders; D006470:Hemorrhage; D006801:Humans; D010641:Phenotype
keywords: anticoagulants; diagnosis; epidemiology; hemorrhage; hemorrhagic disorders